Wireless leaf nodes, such as sensors are networked via multiple infrastructure nodes that communicate with a central controller. The sensors operate at low power to conserve batteries, and increase the time period in which batteries need to be replaced. This implies that the radio frequency (RF) signal generated by a sensor will have extremely low signal strength. The infrastructure nodes are placed throughout the network of sensors and they relay the data from the sensors to the central controller. The infrastructure nodes may be line powered and they may communicate with each other and with the controller at higher signal strength and also at a higher data rate. The RF links between the leaf nodes and the infrastructure nodes as well as the RF links between the infrastructure nodes are highly susceptible to interference and propagation effects, especially in indoor wireless environments. These effects adversely affect the reliability of the entire wireless network.
Robust wireless communication, in the presence of electromagnetic interference (EMI), along with low power consumption by battery powered sensor nodes are important considerations for designing wireless sensor networks for industrial applications. For the proper functioning of the industrial application, the data from the sensors has to be delivered reliably and in a timely manner to the central controller.